1. Democratic donors are excited by the possibility of gaining a House majority.

At ActBlue, the digital fundraising platform used by many Democratic candidates, the House races are just part of a long-running surge. Executive Director Erin Hill said overall fundraising is about to overtake the total for the 2015-16 cycle. "We moved $750 million that cycle," she said. "We're at about 730 now, and it is April."

The surge started with a big bump around January 2017, when President Trump took office. Hill told NPR they wondered why it happened and what it meant. "That was a new administration, people were protesting, and we thought, well, how sustainable can this possibly be? It turns out, incredibly sustainable," she said.

2. In some districts, Democrats "have more well-funded candidates than they know what to do with."

That's how David Wasserman, House editor for the Cook Political Report, assesses it. Donors are so generous this year, Democrats face the prospect of big-budget primaries with multiple candidates burning cash.

"The question is, will those donors consolidate around the eventual nominee? And history tells us that they will," Wasserman said.

The most vulnerable GOP incumbent this year may be two-term Rep. Barbara Comstock, in Virginia's 10th District. She has raised $2.8 million. The top four Democrats vying to challenge her have collectively raised $4 million, but they might use most of it months earlier, in a June primary.

Even then, however, the winner will likely find the money flowing for the fall. Stephen Farnsworth, a political scientist at the University of Mary Washington, said, "When you're talking about the 10th district of Virginia in the age of Donald Trump, money will not be a problem for any viable candidate."

Then there's California, where dueling Democrats in three districts have much more at risk. The states runs its primaries there on a "top two" rule — the two candidates with the most votes go on the November ballot, regardless of party. So if those cash-rich Democrats demolish each other in the spring, Republicans would have a lock in the general election. It's possible that Reps. Dana Rohrabacher (outraised by one of the three strong Democratic challengers) and Ed Royce (outraised by two) could survive this way.

3. Is this another big election for small donors?

For Democrats, yes.

Hill said ActBlue, which mostly handles small contributions, has processed $162 million since January 2017, compared to roughly $99 million in the entire 2015-16 election cycle. She said the average contribution to House candidates through ActBlue is $38.76.

NPR recently examined candidates' disclosure reports for small contributions of $200 or less, a category required by the Federal Election Commission. For all of 2017, Democratic House candidates reported $42.5 million from small donors; Republicans, $14.2 million.

4. Republicans have better access to the biggest of big donors.

If Democrats look strong among small donors, Republicans have strength among wealthier political players. The Democratic National Committee reports raising $81 million for the cycle so far. The Republican National Committee claims $141 million, and recently announced a $250 million program to staff competitive states with canvassers and strategists. The party committees have contribution limits far higher than those for candidates.

There's an even more dramatic split in outside groups — the superPACs, nonprofit groups and other entities that can raise unlimited (and often undisclosed) contributions for political work. The nonpartisan Center for Responsive Politics, which analyzes data from the Federal Election Commission and Internal Revenue Service, lists 20 groups that have spent at least $1 million so far in the 2018 cycle. They've spent $73 million in all, with nearly $54 million — 74 percent — from conservative groups.

This election, with at least 60 House seats in play, the question for both parties will be how and where to focus their spending.

Copyright 2018 NPR. To see more, visit http://www.npr.org/.

AILSA CHANG, HOST:

Congressional candidates have filed their first financial disclosures of this election year, and they make a few things clear. Competitive districts already are attracting a lot of money. And in some districts held by Republicans, more money is being given to unseat them rather than keep them in office. NPR's Peter Overby reports.

PETER OVERBY, BYLINE: Lots of Democratic candidates use ActBlue, a nonprofit fundraising platform that connects them with small donors. Director Erin Hill said it's been setting all sorts of records lately. It first noticed a big bump around January 2017 when President Trump took office. Hill said they thought they could explain it.

ERIN HILL: That was a new administration. People were protesting. And we thought, well, how sustainable can this possibly be? It turns out, incredibly sustainable.

OVERBY: Now, she said, the 2018 midterms are already close to eclipsing the 2016 cycle.

HILL: We moved $750 million that cycle, and we're at about 730 now, and it is April.

OVERBY: The gusher of cash shows up in places like Virginia's 10th District, which includes some of Washington's wealthiest suburbs. The 10th was conservative but now leans more liberal. Republican incumbent Barbara Comstock carried it in 2016. President Trump did not.

Now Comstock has raised nearly $3 million for this November's election. Stephen Farnsworth is a political scientist at Virginia's University of Mary Washington.

STEPHEN FARNSWORTH: When you're talking about the 10th District of Virginia in the age of Donald Trump, money will not be a problem for any viable candidate.

OVERBY: That's certainly true for the top four Democrats running to oppose Comstock. They've each raised between 850,000 and 1.4 million. The primary is in June, and it could stir up trouble for the Democrats.

DAVID WASSERMAN: In a lot of districts, Democrats have more well-funded candidates than they know what to do with.

OVERBY: David Wasserman is the House Editor at The Cook Political Report.

WASSERMAN: In an awful lot of districts, most of the money raised by these candidates up to this point is going to be spent fighting amongst Democrats.

OVERBY: Wasserman cited three districts in California, each with a vulnerable Republican incumbent and multiple million-dollar Democrats. Under California's unique rules, the Democrats could cancel each other out, leaving only two Republicans on the November ballot. But Wasserman generally thinks Democratic enthusiasm will prevail.

WASSERMAN: Question is - will those donors consolidate around the eventual nominee? And history tells us that they will.

OVERBY: More and more, those donors are small donors. Democratic candidates like that. It shows an enthusiastic base of supporters who can be solicited again and again before they hit the legal limit. Some candidates make the point by swearing off the bigger contributions from corporate political action committees.

NPR ran the 2017 small-donor totals for all House candidates. Small-donor contributions are amounts of $200 or less. The grand total for Republican candidates - $14 million. For Democrats - 42 million. But this doesn't necessarily mean a Democratic House majority next year. John Feehery is a Republican lobbyist and strategist.

JOHN FEEHERY: When it comes to the money, the Republicans and the Democrats are roughly tied. Republicans probably have an advantage at the national level.

OVERBY: That's because the Republican National Committee has much more cash than the Democratic National Committee - cash that will pay for canvassers and phone banks to save their House majority.

And conservatives field more of the outside groups - super PACs and social welfare groups - where donors often write seven- or eight-figure checks. Peter Overby, NPR News, Washington.